Tetralluoroethylene

Tetralluoroethylene polymer has the lowest coefficient of friction of any solid. It has remarkable chemical resistance and a very low brittleness temperature ( — 100°C). Its dielectric constant and loss factor are low and stable across a broad temperature and frequency range. Its impact strength is high. 

Ethylene-Tetrafluoroethylene Copolymer. Ethylene-tetralluoroethylene copolymer consists of linear chains in which the repeating unit is... 

The pentafluoride catalyses polymerisation of tetralluoroethylene smoothly below — 100°C, but explosively above that temperature. 

Tetrafluorooxathietane-2,2-dioxide (Tetrafluoroethane sultone) [697-18-7] o / I 2c,, so2 cf2 Preparative hazard See Sulfur trioxide Tetralluoroethylene C2F403S... 

See Bromotrichloromethane, and Carbon tetrachloride, and Chlorotrifluoroethy-lene, all above Tetralluoroethylene, below... 

See LANTHANIDE-TRANSITION METAL ALLOY HYDRIDES See Poly(tetralluoroethylene) Metal hydrides... 

Oxygen Polytetrafluoroethylene, Stainless steel, 4831 Poly(tetralluoroethylene) Oxygen, 0629... 

The thermal [2 + 2] cycloaddition is limited to certain activated alkenes. For instance tetralluoroethylene, tetrachloroethylene, allenes e.g. 17, ketenes and ena-mines can form cyclic dimers or react with other alkenes ... 

The peroxy compound initiated explosive polymerisation of tetralluoroethylene... 

Fonnation from tetralluoroethylene and oxygen may be explosive. It rearranges to trifluoroacetyl fluoride above its b.p.. -63.5°C. 

Banks, R. E. et al., J. Chem. Soc., Perkin Trans. 1, 1974, 2535-2536 During an increased-scale preparation of the dioxyl by permanganate oxidation of the hydrolysate of a nitrosotrifluoromethane-tetralluoroethylene-phosphorus trichloride adduct, an impurity in the dioxyl, trapped out at — 96°C ( — 196°C) and <2.5 mbar, caused a violent explosion to occur when the trap content was allowed to warm up. A procedme to eliminate the hazard is detailed. 

A fluorinated heterocycle, 3,3,4,4-tetrafluoro-l,2-oxathietane-2,2-dioxide more commonly called tetralluoroethylene sultone (XXVll), is the starting material for the synthesis of Nalion perfluorinated ion exchange resins. This compound was synthesized independently at DuPont and the Russian Academy of Sciences by the reaction of tetralluoroethylene and sulfur trioxide (Eq 13.24). 

The monomer XXVIII is copolymerized with tetralluoroethylene to give a polymer-containing pendant fluorosulfonyl groups that are then hydrolyzed and acid exchanged to produce Nafion (XXIX) The resulting polymer combines the chemical, thermal, and oxidative stability of perfluorinated polymers such as polytetra-fluoroethy lene with the properties ofahighly acidic fluorinated sulfonic acid. Nafion is used in a variety of electrochemical applications such as the synthesis of chlorine and caustic and as the conductive membrane of many modern fuel cells. It has also been used in water electrolysis and as an acid catalyst in many proprietary commercial processes. 

Table 6.2 (27) summarizes the crystallographic data of some important polymers. Several polymers have more than one crystallographic form. Poly-tetralluoroethylene (Teflon ), for example, undergoes a first-order crystal-crystal transition at 19°C. 

S-PVC Poly(vinyl chloride), polymerized in sus- TFE Tetralluoroethylene (ASTM)... 

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